Brad Pitt on Angelina Jolie's Mastectomy Decision: "She's a Badass!"

It wasn't just another red carpet premiere for Brad Pitt in London on Sunday, June 2, where the superstar debuted his new zombie epic World War Z. At the actor's side was fiancee Angelina Jolie -- gorgeous in a Saint Laurent floor-length black gown -- in her first public appearance since her preventative double mastectomy, which began in February and which she revealed in the New York Times last month.

Pitt was frank with reporters about the importance of his love's appearance that night. "[Her support is] the same thing it means every time she comes to support me, but this time we don't have that other thing hanging over us that we knew we'd have to deal with at some point - her specifically, physically," Pitt, 49, explained. (After doctors discovered a faulty gene that made Jolie hugely susceptible to breast cancer, the actress opted to undergo the intense procedure.)

"It's a huge relief to know, that's the thing that's not going to take her," Pitt said of the fatal disease. "[Cancer] is not the thing I'm going to have to explain to the kids about why they can't see mom again. It's big, it's everything."

Jolie kept it short and sweet with reporters. "I feel wonderful!" she said. "It's Brad's night."

It was also family night: The couple's eldest sons Maddox, 11, and Pax, 9, were on hand to catch the film with their famous parents. "My boys, they're big zombie fans," Pitt explained to Us Weekly. "That's what first got me focused on [Max Brooks'] book."